Let me see if I can clarify...
The Runner does not have to use a pass for either park during the race. The exception to this would be if the runner was staying at an Epcot Resort (Boardwalk, Beach, Yacht and Swan/Dolphin) and decided to walk back through Epcot to the resort. If that is the basis of the question, simply ride the bus back to the resort and you can burn you pass where you want.
The Spectator does not need a pass to view you along most of the course including the finish line area. The spectator has access to Main Street in Magic Kingdom during the race. The exception would be if the spectator decided to enter Epcot after it opens and watch from there. I frankly discourage that as the views are just not that great, the area to watch is relatively small and there are throngs of non-race guests trying to get to the rides. Plus most of the field will clear Epcot before park open.
I am not sure if I helped, if not ask again